A conventional oscillating pump, such as shown in U.S. Pat. No. 5,915,930, includes a valve sleeve which carries a center valve. The sleeve fits within a recessed area formed in an elastomeric impeller. The impeller, which thus carries the sleeve and the valve, is then positioned in a metallic armature.
It has been found that after extended operation of such a pump, the pressure generated by the pump oftentimes causes the impeller to stretch thin, and eventually rupture, at the already thinned-out, recessed area which holds the sleeve.
Thus, the need exists for a system of positioning and retaining a center valve sleeve in an oscillating pump which will eliminate the fatigue on the impeller.